as.SpatialPolygons.GridTopology

0th

Percentile

Make SpatialPolygons object from GridTopology object

Converts grids of regular rectangles into a SpatialPolygons object, which can be transformed to a different projection or datum with spTransform in package rgdal. The function is not suitable for high-resolution grids. The ordering of the grid cells is as in coordinates() of the same object, and is reported by IDvaluesGridTopology.

Keywords
spatial
Usage
as.SpatialPolygons.GridTopology(grd, proj4string = CRS(as.character(NA))) IDvaluesGridTopology(obj) as.SpatialPolygons.SpatialPixels(obj) IDvaluesSpatialPixels(obj) HexPoints2SpatialPolygons(hex, dx)
Arguments
grd
GridTopology object
proj4string
object of class CRS-class
obj
SpatialPixels object
hex
SpatialPoints object with points that are generated by hexagonal sampling; see spsample
dx
spacing of two horizontally adjacent points; if missing, this will be computed from the points
Value

as.SpatialPolygons.GridTopology and as.SpatialPolygons.SpatialPixels return a SpatialPolygons object; IDvaluesGridTopology and IDvaluesSpatialPixels return a character vector with the object grid indices.

See Also

GridTopology, SpatialPixels, SpatialPolygons spTransform in package rgdal

Aliases
  • as.SpatialPolygons.GridTopology
  • coerce,GridTopology,SpatialPolygons-method
  • HexPoints2SpatialPolygons
  • IDvaluesGridTopology
  • as.SpatialPolygons.SpatialPixels
  • coerce,SpatialPixels,SpatialPolygons-method
  • IDvaluesSpatialPixels
Examples
library(lattice)
grd <- GridTopology(cellcentre.offset=c(-175,55), cellsize=c(10,10), cells.dim=c(4,4))
SpP_grd <- as.SpatialPolygons.GridTopology(grd)
plot(SpP_grd)
text(coordinates(SpP_grd), sapply(slot(SpP_grd, "polygons"), function(i) slot(i, "ID")), cex=0.5)
trdata <- data.frame(A=rep(c(1,2,3,4), 4), B=rep(c(1,2,3,4), each=4),
 row.names=sapply(slot(SpP_grd, "polygons"), function(i) slot(i, "ID")))
SpPDF <- SpatialPolygonsDataFrame(SpP_grd, trdata)
spplot(SpPDF)

data(meuse.grid)
gridded(meuse.grid)=~x+y
xx = spsample(meuse.grid,  type="hexagonal", cellsize=200)
xxpl = HexPoints2SpatialPolygons(xx)
image(meuse.grid["dist"])
plot(xxpl, add = TRUE)
points(xx, cex = .5)
## Not run: 
# spplot(aggregate(meuse.grid[,1:3], xxpl), main = "aggregated meuse.grid")
# ## End(Not run)
Documentation reproduced from package sp, version 1.2-3, License: GPL (>= 2)

Community examples

Looks like there are no examples yet.